The sand was white, but the murky, brownish waters of some beaches in Collier County and South Lee continued to drive some potential swimmers away on Monday.

Discolored waters have been reported in several places, including Barefoot Beach, Seagate Beach and Naples Pier, according to Stephanie Molloy, Natural Resources Manager in Naples. Beach lovers on social media have also reported a similar discoloration at Bonita Beach on Sunday.

But while waves of red tide have ravaged beaches and marine life in southwestern Florida for months, the discoloration is caused by the proliferation of a nontoxic diatom, called Cylindrotheca, said Molloy.

"There are many different species," she said. "When conditions are good, they flourish."

But unlike the red tide, which can cause breathing problems and coughing for swimmers, the diatom does not produce toxin, Molloy said.

"This is not a risk to human health," she said.

Michael Parsons, professor of marine science at the Florida Coast Coast University, said the diatom could grow "much faster" than the red tide body, Karenia brevis, and could well win the battle for the nutrients contained in the water.

"Diatoms will almost always be outmatched," said Parsons, director of FGCU Coastal Watershed Institute and Vester Marine & Environmental Science Research Station.

Diatoms tend to grow well in quieter waters, he said.

"This year it was pretty quiet," said Parsons.

More: The troubled waters of the quai de Naples keep swimmers away

The water at Sanibel's Bowman's Beach has also been bleached by the proliferation of another microorganism, a dinoflagellate like the one that causes the red tide, called Peridinium, "but it's not toxic," said researcher Rick Bartles of the Sanibel-Captiva Conservation Foundation.

In Lee County, the number of red tide cells has been reduced recently, but not enough to call it a trend, he said.

Crabs that live at the bottom and those that crawl slowly die and get covered with a layer of black mud that forms when the rise of oxygen in water is missing to replace the surface water contacts. with dissolved iron, which causes the resulting iron sulphide to precipitate out of the water, Bartleson said.

On Monday, beachgoers could still find dead eels, smaller crabs and fish scattered on the shores of Collier.

Although the diatom responsible for water discoloration is not toxic, it can contribute to an imbalance of oxygen levels in the water, which can lead to fish death if the levels in the water are low. Oxygen drops enough, said Parsons.

Herbaceous eels are "probably more sensitive" to low levels of oxygen and they are essentially choking, he said, which may explain why they are getting rid of them now.

In Collier, the brown waters began to appear last week and have shuttled between Barefoot Beach and Naples Pier, said Rhonda Watkins, senior operations analyst at Collier County Pollution Control.

"Most of Naples' beaches also have low levels of oxygen and species that are not usually affected by the red tide toxin (crabs and sands dollars) are dying for lack of oxygen", said Watkins in an email. "We still have red tide on some beaches and off the coast of Collier."

More: Scientists will test samples of thick green algae spotted at Bonita Springs

Watkins recommended people sensitive to the red tide or suffering from chronic respiratory diseases to avoid the beach.

Automatic reading

Thumbnails poster

Show captions

Last slide next

"Other groundfish such as flounder, eels, bat fish and toad fish die and fall to the ground, which could result from a combination of toxin from the tide." red and lack of oxygen, "she wrote.

The only beach in Collier that currently does not have any discolored water or dead fish seems to be Marco Island, said Watkins, although she adds that the flowers are "very uneven and conditions can change quickly".

Matt Wells, who works at Cabana Dan's in Vanderbilt Beach, said he had begun noticing the discoloration of "brown coffee" about four days ago.

Few bathers, if any, went to the seaside on Sunday, causing the small concession hut to close early "simply because there were no customers on the beach", did it? he declares.

"Nobody was going in the water," said Wells.

On Monday morning, a similar picture was shown at Vanderbilt Beach and the Naples Pier: beachgoers sitting on chairs and towels enjoying the sun, most people heading for open water.

Wells said that he was observing a different species washing himself almost every week.

"Last week we had a lot of blue-shelled crabs," he said. "This week we had a lot of eels, which are abnormal here and are struggling."

TO CLOSE

Mallorey Stack shared videos showing several dolphins swimming near the shore along Naples Beach on Saturday, September 29, 2018.
Submitted by Mallorey Stack, Naples Daily News

Kevin Swede was one of the few to have faced the brown sea on Monday morning, having sailed to the sea from a boat where he was to see what the weather was like by the sea.

He estimated that the brownish discoloration had reached about 100 meters from the shore in the Gulf, where the water was clearer.

"When we came in, obviously, it's brownish, brackish water," said the 32-year-old Swede. "Dead eels, shrimps, crabs, but if you go out a little further, it's a bit like it's normal."

More: The proliferation of algae on Lake O has groups, scientists involved

The center of Naples, Roger Jacobsen, said that he remembered similar conditions on local beaches about ten years ago. At the time, "everyone thought it was a spill," he said.

"Because he's got almost that (look)," Jacobsen said. "Especially when we look at what's accumulating … And it's not … it's not a spill."

But a respite from the dark conditions may be in sight.

Parsons, the FGCU scientist, said prediction models predict east and southeast winds this week, which would help push diatoms back into the poorer Gulf of nutrients.

There, the diatoms "would starve" and dissipate, he said.

Fort Myers News-Press reporter Amy Bennett Williams contributed to this story.

How can you help

Officials are asking the public for help to report beach conditions, good or bad, with the help of a smartphone app called MOTE CSIC.

The Marine Laboratory and the Mote Marine Aquarium in Sarasota, the NOAA, the FWC and the University of South Florida use this information to track and predict harmful algal blooms.

Beach lovers can also check local conditions before going on www.visitbeaches.org.

Read or share this story: https://www.naplesnews.com/story/news/local/environment/2018/10/01/red-tide-not-culot-case-southwest-floridas-murky-waters/1489416002/